*Smoking, obesity, type 2 diabetes raise pancreatic tumour risk
A cancer vaccine that cured 97 percent of blood tumours in mice will be tested on humans with low-grade lymphoma later this year.Patients receiving the vaccine, which contains two drugs proven for their safety, will not require any chemotherapy, with the jab’s side effects expected to be just fever and injection-site soreness.
If approved, researchers do not expect the treatment to be available for another year or two.Rather than creating lasting immunity, the jab works by activating the immune system to attack tumours.This is expected to be effective in low-grade lymphoma, which affects certain white blood cells and generally responds to treatment, due to it often being detected by the immune system, unlike other forms of the disease, such as bowel cancer.
The findings were published in the journal Science Translational Medicine. Lead author Dr. Ronald Levy, from Stanford University, said: “We have a huge problem in cancer and we will never be satisfied until we find solutions for everyone.”What the study will involve? The vaccine will be tested across two studies. A total of 35 lymphoma patients will take part in the trials overall.
Each participant will receive a low dose of radiation alongside two rounds of the vaccine over six weeks. Further details, such as the time between vaccines, are unclear.A similar immune-system targeting approach is already approved for types of leukemia and lymphoma.
This involves removing immune cells from patients’ bodies and genetically engineering them to attack tumours before they are reintroduced.Yet such a treatment, known as CAR-T, costs around half a million dollars per patient and can cause fever, confusion, organ failure, and immune-system dysfunction.
Cancer specialist Dr. Michelle Hermiston, from the University of California, San Fransisco, said: “It’s not a trivial therapy.”She adds research should be carried out to determine if tumours can be manipulated to make them respond better to the immune system.Hermiston said: “Can we make the tumor more visible to the immune system? We are at the tip of the iceberg right now.”
The researchers implanted two identical tumours in separate sites in mice’s bodies.One of these tumours was injected with the vaccine, which triggered the activation of T cells. Such cells launch an immune response against invading substances, such as viruses, in animals’ bodies.
The degree of response was measured by the jab’s effect on the untreated tumour.Results suggest the vaccine cures multiple types of cancer and prevents the disease from occurring.
Also, researchers have associated the rise in cases of pancreatic cancer with smoking, obesity, type 2 diabetes, and hypertension. They said there are multiple intersecting factors at work. The rising rank in mortality is, in some ways, a good thing; it reflects advances in battling other malignancies. Better screening and treatment have meant that patients with other types of cancer—particularly breast, prostate and colon cancer—are living long enough to die of something else. Unfortunately, innovations such as immunotherapy have not worked well for pancreatic cancer, so along with liver cancer, it is causing an outsize and growing portion of cancer-related deaths.
The expanding caseload is a little harder to explain. Some of it, too, reflects progress: refined ways of testing biopsied tissue and higher-resolution imaging have meant that mystery tumors that once couldn’t be seen or were labeled “of unknown origin” can now be identified, and some turn out to be pancreatic.
The aging of our population also contributes: it’s pushing up the rates of many kinds of cancer. The longer we live, the more we accumulate genetic errors that can cause tumors and the less effective our DNA cleanup crew becomes.
In the case of pancreatic cancer, more than three quarters of new patients are between 55 and 84 years old.Other forces are at work as well. Smokers face more than twice a nonsmoker’s risk of pancreatic cancer, and even though smoking has slumped in the U.S., there is a 30- to 40-year lag time before we see a corresponding drop in cancer rates. In theory, pancreatic cancer should be waning, thanks to the dramatic falloff in smoking that began in the 1970s. But sadly, a new villain on the block is taking up some of the slack: soaring rates of obesity and type 2 diabetes, which are also risk factors.
Oncologist Robert A. Wolff has been treating pancreatic cancer at the University of Texas MD Anderson Cancer Center for 20 years. “Since I’ve been practicing, I’ve seen a shift from smoking to obesity as the driver,” he says. “An average patient of mine has a body mass index between 30 and 35 [obesity is defined as 30 or more], has diabetes or prediabetes, is hypertensive and takes a lipid-lowering agent.” Toss in a history of smoking, and such patients, he says, “are just time bombs for pancreatic cancer.”
Obesity and type 2 diabetes raise the risk of many forms of cancer. Among the suspected reasons: chronic low-level inflammation, too much insulin, excess hormones and growth factors released by fat tissue, and metabolic abnormalities.
Researchers are looking for early signs of pancreatic cancer in the blood or tissue of adults age 50 and older who were newly diagnosed with diabetes. Nearly one percent of such adults will develop the disease within three years, says Lola Rahib, a scientist at the Pancreatic Cancer Action Network, which supports the research. The challenge, she says, is to find biomarkers precise enough to avoid “costly and emotional” false positives and negatives. The quest for cancer blood tests—known as liquid biopsies—is one of the hottest areas in oncology, notes Otis Brawley, chief medical and scientific officer at the American Cancer Society, but there’s a long way to go: “The tests reported so far have really terrible specificity.”
Even if blood tests could someday detect pancreatic cancer at an early stage, treatment would have to improve a lot for them to do much good. Unlike many cancers that are curable if detected early, pancreatic tumors are quick to metastasize. “The cells break away like a crumbling popcorn ball,” Brawley says. Still, some modest progress has been made. Five-year survival rates for pancreatic cancer have inched up from 6 to 9 percent in recent years.
Wolff believes that newer, precision medicine therapies will ultimately help his patients, particularly the 10 percent or so whose cancer is more driven by heredity than way of life. But the bigger message is prevention, he says: “It’s thought that easily 30 percent of pancreatic cancer is preventable. Cutting back on obesity, better diets, more exercise, no smoking. What a concept!”
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